An image pickup apparatus that changes an image capturing direction by activating a pan head has been known. In addition, an image pickup apparatus that changes a direction in which the image pickup apparatus captures an image, in response to an instruction sent from a control apparatus connected to the image pickup apparatus via a network has been known. In these image pickup apparatuses, when the setup state of each image pickup apparatus is changed, the direction in which the image pickup apparatus captures an image in response to the same command is different before and after the change.
For example, the case in which the setup state of an image pickup apparatus is changed from a state in which the image pickup apparatus is set to be upright to a state in which the image pickup apparatus is set to be flat and placed on a ceiling or the like will be described. When a command for causing the image capturing direction of an image pickup apparatus that has been set to be upright to be directed upward is given to an image pickup apparatus that has been set to be flat, the image pickup apparatus operates so that the image capturing direction is directed downward. When the setup state of the image pickup apparatus is changed from being upright to being flat, the direction in which the image pickup apparatus captures an image in response to the same command is inverted between top and bottom and between left and right.
To this end, an image pickup system that has plural control programs for changing the direction in which an image pickup apparatus captures an image and that switches a control program to use in accordance with the setup orientation of the image pickup apparatus is known (for example, see Patent Literature). In the image pickup system, the coordinate system for representing the image capturing direction in terms of coordinates is switched by switching the control program. Accordingly, regardless of the setup state, the image capturing direction of the image pickup apparatus can always be directed to a certain direction in response to a particular command.